Research on laser welding of high-strength galvanized automobile steel sheets

• Published in: Optics and lasers in engineering Vol. 47; no. 11; pp. 1117 - 1124
• Main Authors: Mei, Lifang, Chen, Genyu, Jin, Xiangzhong, Zhang, Yi, Wu, Qiang
• Format: Journal Article
• Language: English
• Published: Kidlington Elsevier Ltd 01.11.2009; Elsevier
• Subjects: Biological and medical applications; Deep-penetration laser welding; Exact sciences and technology; Fundamental areas of phenomenology (including applications); Gas lasers including excimer and metal-vapor lasers; High-strength galvanized steel; Industrial applications; Lasers; Mechanical properties; Optics; Parameter optimization; Physics; Zinc vaporization; Mechanical properties; Deep-penetration laser welding; Zinc vaporization; High-strength galvanized steel; Parameter optimization; Galvanized steel; Optimization method; Laser assisted processing; Laser beam applications; Laser welding; Zinc; Manufacturing; Argon; Gas lasers; Microstructure; Carbon dioxide lasers
• ISSN: 0143-8166; 1873-0302
• DOI: 10.1016/j.optlaseng.2009.06.016

The paper presented some useful results of deep-penetration laser welding of high-strength galvanized steel sheets, which had been carried out by a self-made CO 2 laser unit with maximum power output of 1.5 kW. The workpieces of high-strength galvanized automobile steels with thickness of 1.5 mm were butt-welded with argon as the shielding gas. The effects of such factors as laser power, welding speed, focal position, shielding gas and zinc vaporization on the quality of welds are investigated. With the processing parameters optimized and the proper shielding gas used in both coaxial and side-blow direction, most of the defects, such as pores, cracks and softening in HAZ, can be avoided in laser welding joints. The microstructure, the hardness distribution and the elemental distribution in the welding joints can be changed due to laser heating and recrystallization. In order to determine the mechanical properties of the welding joints, the static tensile strength was tested. Experimental results indicated that both the strength and microhardness of welding joints were higher than those of the base metal. Consequently, the welding quality is reliable for manufacturing of automobile bodies.